Purification and characterization of a novel stress protein, the 150-kDa oxygen-regulated protein (ORP150), from cultured rat astrocytes and its expression in ischemic mouse brain

Differences in the expression of myelopathy in a rat model of chronic spinal cord compression

CONTEXT/OBJECTIVE

The degree of spinal cord compression does not always parallel neurological symptoms. We considered that some compensatory neuroprotective mechanism underlies the expression of this neurological phenotype. Oxygen-regulated-protein 150 (ORP150) is neuroprotective and expressed in neurons in response to neuronal ischemia. We sought to elucidate whether ORP150 expression is associated with the severity and variation of neurological recovery in our rat model of chronic spinal cord compression.

METHODS

We made a rat model of chronic spinal cord compression inserting an expandable water-absorbing polyurethane sheet. A neurological behavioral assessment of the severity of paralysis was performed for 10 weeks postoperatively. The rat model was defined as two groups: a myelopathy group with decreased locomotor function and an asymptomatic group. At 10 weeks postoperatively, the spinal cord of the cervical segment was resected for histology and qPCR.

RESULTS

Slowly progressive paralysis appeared at 5-10 weeks postoperatively in 53% of the rats with spinal cord compression. The asymptomatic group had no histological changes indicative of myelopathy. Histology and qPCR showed increased expression of ORP150 in the asymptomatic group, but the ratio of ORP150-positive neuron in the two groups was not significantly different.

CONCLUSION

The expression of ORP150 in neurons associated with spinal cord compression suggested that the spinal cord was under ischemic stress due to compression, but relation to the development of myelopathy was unclear. The results suggested that some other compensatory mechanisms may exist in response to spinal cord compression in asymptomatic rats.

Systemic proteome adaptions to 7-day complete caloric restriction in humans

Surviving long periods without food has shaped human evolution. In ancient and modern societies, prolonged fasting was/is practiced by billions of people globally for religious purposes, used to treat diseases such as epilepsy, and recently gained popularity as weight loss intervention, but we still have a very limited understanding of the systemic adaptions in humans to extreme caloric restriction of different durations. Here we show that a 7-day water-only fast leads to an average weight loss of 5.7 kg (±0.8 kg) among 12 volunteers (5 women, 7 men). We demonstrate nine distinct proteomic response profiles, with systemic changes evident only after 3 days of complete calorie restriction based on in-depth characterization of the temporal trajectories of ~3,000 plasma proteins measured before, daily during, and after fasting. The multi-organ response to complete caloric restriction shows distinct effects of fasting duration and weight loss and is remarkably conserved across volunteers with >1,000 significantly responding proteins. The fasting signature is strongly enriched for extracellular matrix proteins from various body sites, demonstrating profound non-metabolic adaptions, including extreme changes in the brain-specific extracellular matrix protein tenascin-R. Using proteogenomic approaches, we estimate the health consequences for 212 proteins that change during fasting across ~500 outcomes and identified putative beneficial (SWAP70 and rheumatoid arthritis or HYOU1 and heart disease), as well as adverse effects. Our results advance our understanding of prolonged fasting in humans beyond a merely energy-centric adaptions towards a systemic response that can inform targeted therapeutic modulation.

METTL3/IGF2BP3-regulated m6A modification of HYOU1 confers doxorubicin resistance in breast cancer

Chemoresistance is a main reason for therapeutic failure and poor prognosis for breast cancer (BC) patients, especially for triple-negative BC patients. How the molecular mechanisms underlying the chemoresistance to doxorubicin (Dox) in BC is not well understood. Here, we revealed that METTL3/IGF2BP3-regulated m6A modification of HYOU1 increased Dox resistance in BC cells. CCK-8 and Annexin V-FITC/PI staining assays were employed to measure viability and cell death. Western blotting and qRT-PCR assays were applied to assay the expression of genes. Knockdown and rescue experiments were used to assay the role of METTL3, IGF2BP3 and HYOU1 in regulating BC cell responses to Dox. RIP, MeRIP and dual-luciferase activity assays were applied to examine the function of METTL3/IGF2BP3 in the m6A modification of HYOU1 mRNA. It was found that global mRNA m6A methylation levels were upregulated in Dox-resistant BC cell lines. The methyltransferase METTL3 was upregulated in Dox-resistant BC cell lines, and downregulation of METTL3 could overcome this resistance. Furthermore, HYOU1 was identified as a downstream target of METTL3-mediated m6A modification. Downregulation of HYOU1 could overcome Dox resistance, while forced expression of HYOU1 resulted in Dox resistance in BC cells. METTL3 cooperated with IGF2BP3 to modulate the m6A modification of HYOU1 mRNA and increase its stability. Collectively, our findings unveiled the key roles of the METTL3/IGF2BP3/HYOU1 axis in modulating Dox sensitivity in BC cells; thus, targeting this axis might be a potential strategy to increase Dox efficacy in the treatment of BC.

Unveiling the dark side of glucose-regulated protein 78 (GRP78) in cancers and other human pathology: a systematic review

Glucose-Regulated Protein 78 (GRP78) is a chaperone protein that is predominantly expressed in the lumen of the endoplasmic reticulum. GRP78 plays a crucial role in protein folding by assisting in the assembly of misfolded proteins. Under cellular stress conditions, GRP78 can translocate to the cell surface (csGRP78) were it interacts with different ligands to initiate various intracellular pathways. The expression of csGRP78 has been associated with tumor initiation and progression of multiple cancer types. This review provides a comprehensive analysis of the existing evidence on the roles of GRP78 in various types of cancer and other human pathology. Additionally, the review discusses the current understanding of the mechanisms underlying GRP78's involvement in tumorigenesis and cancer advancement. Furthermore, we highlight recent innovative approaches employed in downregulating GRP78 expression in cancers as a potential therapeutic target.

Tissue-Specific Analysis of Alternative Splicing Events and Differential Isoform Expression in Large Yellow Croaker (Larimichthys crocea) After Cryptocaryon irritans Infection

The large yellow croaker (Larimichthys crocea) is one of the most important mariculture fish in China. Recently, cryptocaryonosis caused by Cryptocryon irritans infection has brought huge economic losses and threatens the healthy and sustainable development of the L. crocea industry. However, the molecular mechanism and regulation process for L. crocea resistance to C. irritans infection has not been fully researched. Alternative splicing (AS) is an important post-transcriptional regulatory mechanism that allows cells to produce transcriptional and proteomic diversity. The results of AS are tissue dependent, and the expression of tissue-specific transcription subtype genes is determined by AS and transcriptional regulation. However, studies on the tissue specificity of AS events in L. crocea following infection with C. irritans have not been performed. In this study, the L. crocea were artificially infected with C. irritans; their skin and gill were collected at 0 h, 24 h, 48 h, 72 h, and 96 h post infection. After sequencing and differential expression analysis, a set of 452, 692, 934, 711, 534, and 297 differential alternative splicing (DAS) events were identified in 0 h, 12 h, 24 h, 48 h, 72 h, and 96 h post infection respectively. Furthermore, 4160 differentially expressed isoforms (DEIs) and 4209 DEI genes were identified from all time point groups. GO enrichment and pathway analysis indicated that many genes of DAS and DEIs were rich in immune-related GO terms and KEGG pathways, such as the Toll and Imd signaling pathway, NOD-like receptor signaling pathway, TNF signaling pathway, and TNF signaling pathway. Among hub DEI genes, alternative splicing-related genes (cwc25, prpf8, and sf3a3), skin function-related gene (fa2h), and oxygen deprivation-related gene (hyo1) were found in DEI genes. This study provided insight into the temporal change of DAS and DEIs between skin and gill of L. crocea against C. irritans infection and revealed that these differences might play immune-related roles in the infection process.

Recurrent Infections and Immunodeficiency Caused by Severe Pancytopenia Associated with a Novel Life-Threatening Mutation in Hypoxia-Upregulated Protein 1

HYOU1 encodes a protein from the endoplasmic reticulum chaperone proteins, expressed to protect cellular mechanisms from stress such as hypoxia, insufficient energy and excessive or insufficient substances, and to restore cell homeostasis. In this study, we report a novel pathogenic variant in HYOU1. The proband, the second patient with pathogenic variant in HYOU1, was a female born to consanguineous parents. A novel homozygous pathogenic variant in HYOU1 (NM_001130991.3: c.1456C>T; p.Arg486Cys) was identified, causing anemia, thrombocytopenia and severe panleukopenia and immunodeficiency in the second month of age, leading to consistent high-grade fever, regression of brain functions and recurrent infections; ultimately resulting in the patient expiring at three and half months of age. Both parents are heterozygous for this variant and have no issues related to this study.

Early Emergence of Adaptive Mechanisms Sustaining Ig Production: Application to Antibody Therapy

Antibody therapy, where artificially-produced immunoglobulins (Ig) are used to treat pathological conditions such as auto-immune diseases and cancers, is a very innovative and competitive field. Although substantial efforts have been made in recent years to obtain specific and efficient antibodies, there is still room for improvement especially when considering a precise tissular targeting or increasing antigen affinity. A better understanding of the cellular and molecular steps of terminal B cell differentiation, in which an antigen-activated B cell becomes an antibody secreting cell, may improve antibody therapy. In this review, we use our recently published data about human B cell differentiation, to show that the mechanisms necessary to adapt a metamorphosing B cell to its new secretory function appear quite early in the differentiation process i.e., at the pre-plasmablast stage. After characterizing the molecular pathways appearing at this stage, we will focus on recent findings about two main processes involved in antibody production: unfolded protein response (UPR) and endoplasmic reticulum (ER) stress. We’ll show that many genes coding for factors involved in UPR and ER stress are induced at the pre-plasmablast stage, sustaining our hypothesis. Finally, we propose to use this recently acquired knowledge to improve productivity of industrialized therapeutic antibodies.

Amino acid restriction alters survival mechanisms in pancreatic beta cells: possible role of the PI3K/Akt pathway

Background and aims

Malnutrition in the early stages of life may lead to changes in the glycemic metabolism during adulthood, such as pancreatic beta cells dysfunction and failure. Therefore, this study aimed to evaluate the effects of an in vitro amino acid restriction model on the function and viability of pancreatic beta cells.

Methods

Insulin-producing cells (INS-1E) were maintained in control or amino acid restricted culture medium containing 1 × or 0.25 × of amino acids, respectively, for 48 h.

Results

Amino acid restricted group showed lower insulin secretion and insulin gene expression, reduced mitochondrial oxygen consumption rate and reactive oxygen species production. Besides, amino acid restricted group also showed higher levels of endoplasmic reticulum stress and apoptosis markers and enhanced Akt phosphorylation. However, even with higher levels of apoptosis markers, amino acid restricted group did not show higher levels of cell death unless the PI3K/Akt pathway was inhibited.

Conclusion

Amino acid restricted beta cell viability seems to be dependent on the PI3K/Akt pathway.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02568-2.

Biological Function of HYOU1 in Tumors and Other Diseases

Various stimuli induce an unfolded protein response to endoplasmic reticulum stress, accompanied by the expression of endoplasmic reticulum molecular chaperones. Hypoxia-upregulated 1 gene (HYOU1) is a chaperone protein located in the endoplasmic reticulum. HYOU1 expression was upregulated in many diseases, including various cancers and endoplasmic reticulum stress-related diseases. HYOU1 does not only play an important protective role in the occurrence and development of tumors, but also is a potential therapeutic target for cancer. HYOU1 may also be used as an immune stimulation adjuvant because of its anti-tumor immune response, and a molecular target for therapy of many endoplasmic reticulum-related diseases. In this article, we summarize the updates in HYOU1 and discuss the potential therapeutic effects of HYOU1.

Transcriptomic analysis of Pacific white shrimp (Litopenaeus vannamei, Boone 1931) in response to acute hepatopancreatic necrosis disease caused by Vibrio parahaemolyticus

Acute hepatopancreatic necrosis disease (AHPND), caused by marine bacteria Vibrio Parahaemolyticus, is a huge problem in shrimp farms. The V. parahaemolyticus infecting material is contained in a plasmid which encodes for the lethal toxins PirABVp, whose primary target tissue is the hepatopancreas, causing sloughing of epithelial cells, necrosis, and massive hemocyte infiltration. To get a better understanding of the hepatopancreas response during AHPND, juvenile shrimp Litopenaeus vannamei were infected by immersion with V. parahaemolyticus. We performed transcriptomic mRNA sequencing of infected shrimp hepatopancreas, at 24 hours post-infection, to identify novel differentially expressed genes a total of 174,098 transcripts were examined of which 915 transcripts were found differentially expressed after comparative transcriptomic analysis: 442 up-regulated and 473 down-regulated transcripts. Gene Ontology term enrichment analysis for up-regulated transcripts includes metabolic process, regulation of programmed cell death, carbohydrate metabolic process, and biological adhesion, whereas for down-regulated transcripts include, microtubule-based process, cell activation, and chitin metabolic process. The analysis of protein- protein network between up and down-regulated genes indicates that the first gene interactions are connected to oxidation-processes and sarcomere organization. Additionally, protein-protein networks analysis identified 20-top highly connected hub nodes. Based on their immunological or metabolic function, ten candidate transcripts were selected to measure their mRNA relative expression levels in AHPND infected shrimp hepatopancreas by RT-qPCR. Our results indicate a close connection between the immune and metabolism systems during AHPND infection. Our RNA-Seq and RT-qPCR data provide the possible immunological and physiological scenario as well as the molecular pathways that take place in the shrimp hepatopancreas in response to an infectious disease.

The 150-kDa oxygen-regulated protein (ORP150) regulates proteinuria in diabetic nephropathy via mediating VEGF

The 150-kDa oxygen-regulated protein (ORP150) belongs to a family of the heat shock protein implicated in the cellular response to environmental stress. Previous data demonstrated that ORP150 regulates the secretion of vascular endothelial growth factor (VEGF) to drive progression of angiogenesis associated with proliferative diabetic retinopathy. However, the expression and biological functions of serum ORP150 levels in diabetic nephropathy (DN) remain unclear. In this study, we reported for the first time that ORP150 was up-regulated in serum of patients with DN. Moreover, we observed the dramatic increase in serum ORP150 accompanied with the elevated levels of proteinuria and serum VEGF levels in DN, indicating the possible involvement of ORP150 in regulation of albuminuria via mediating VEGF in DN. Employing the streptozotocin (STZ) to construct the DN model, we confirmed the positive correlation of ORP150 with VEGF in vivo. Monoclonal anti-ORP150 antibodies treatment significantly decreased the secretion of VEGF and albuminuria in STZ-induced DN models. Consequently, our data suggested that ORP150 levels were positively correlated with proteinuria burden via mediating VEGF in DN. It may be considered as a novel diagnostic and therapeutic target.

Association of 150-kDa oxygen-regulated protein with vascular endothelial growth factor in proliferative diabetic retinopathy

PURPOSE

150-kDa oxygen-regulated protein (ORP150), a member of heat-shock protein family located in endoplasmic reticulum (ER), has a critical role in secretion of vascular endothelial growth factor (VEGF). We investigated expression levels of ORP150 and correlated these levels with VEGF and total vitreous antioxidant capacity (TAC) in proliferative diabetic retinopathy (PDR). We also examined expression of ORP150 in retinas of diabetic rats and in human retinal microvascular endothelial cells (HRMEC).

METHODS

Vitreous samples from 40 PDR and 20 non-diabetic patients, epiretinal membranes from 14 patients with PDR, retinas of rats and HRMEC were studied by enzyme-linked immunosorbent assay, immunohistochemistry and Western blot analysis.

RESULTS

We showed a significant increase in expression of VEGF and ORP150 in vitreous samples from PDR patients compared with controls (p < 0.0001 for both comparisons). Total vitreous antioxidant capacity (TAC) levels were significantly lower in patients with PDR than those in controls (p < 0.0001). Vascular endothelial growth factor (VEGF) and ORP150 levels in PDR with active neovascularization were significantly higher than that in inactive PDR (p = 0.016; p = 0.011, respectively). A significant positive correlation was observed between levels of ORP150 and levels of VEGF (r = 0.42; p = 0.001). In epiretinal membranes, ORP150 was expressed in vascular endothelial cells and stromal cells. We also demonstrated colocalization of the nuclear cell proliferation marker Ki67 and ORP150 in endothelial cells of pathologic new blood vessels. 150-kDa oxygen-regulated protein (ORP150) levels were significantly increased in rat retinas after induction of diabetes. Vascular endothelial growth factor (VEGF) and the pro-inflammatory cytokines interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) induced upregulation of ORP150 in HRMEC.

CONCLUSION

These results suggest a role for ORP150 in PDR angiogenesis.

Role of the unfolded protein response in the development of central nervous system

The unfolded protein response (UPR) is an intracellular homeostatic signalling pathway that is induced by accumulated misfolded/unfolded proteins in the endoplasmic reticulum (ER). The UPR is closely associated with the development of disease in several tissues, including the central nervous system (CNS), in response to ER stress. More recently, the unique features and importance of the UPR have been revealed in neural stem cells (NSCs) and differentiated CNS cells [neurons and glial cells (astrocytes and oligodendrocytes)]. Although several UPR signalling pathways dynamically change in each CNS cell during brain development, the role of UPR signalling in CNS cells (especially NSCs and glial cells) under pathological or physiological conditions is poorly understood. Here, we discuss and summarize the recent progress in understanding how the UPR regulates the proliferation, differentiation, maturation and viability of CNS cells.

Investigations into Hypoxia and Oxidative Stress at the Optic Nerve Head in a Rat Model of Glaucoma

The vascular hypothesis of glaucoma proposes that retinal ganglion cell axons traversing the optic nerve head (ONH) undergo oxygen and nutrient insufficiency as a result of compromised local blood flow, ultimately leading to their degeneration. To date, evidence for the hypothesis is largely circumstantial. Herein, we made use of an induced rat model of glaucoma that features reproducible and widespread axonal transport disruption at the ONH following chronic elevation of intraocular pressure. If vascular insufficiency plays a role in the observed axonal transport failure, there should exist a physical signature at this time point. Using a range of immunohistochemical and molecular tools, we looked for cellular events indicative of vascular insufficiency, including the presence of hypoxia, upregulation of hypoxia-inducible, or antioxidant-response genes, alterations to antioxidant enzymes, increased formation of superoxide, and the presence of oxidative stress. Our data show that ocular hypertension caused selective hypoxia within the laminar ONH in 11/13 eyes graded as either medium or high for axonal transport disruption. Hypoxia was always present in areas featuring injured axons, and, the greater the abundance of axonal transport disruption, the greater the likelihood of a larger hypoxic region. Nevertheless, hypoxic regions were typically focal and were not necessarily evident in sections taken deeper within the same ONH, while disrupted axonal transport was frequently encountered without any discernible hypoxia. Ocular hypertension caused upregulation of heme oxygenase-1—an hypoxia-inducible and redox-sensitive enzyme—in ONH astrocytes. The distribution and abundance of heme oxygenase-1 closely matched that of axonal transport disruption, and encompassed hypoxic regions and their immediate penumbra. Ocular hypertension also caused upregulations in the iron-regulating protein ceruloplasmin, the anaerobic glycolytic enzyme lactate dehydrogenase, and the transcription factors cFos and p-cJun. Moreover, ocular hypertension increased the generation of superoxide radicals in the retina and ONH, as well as upregulating the active subunit of the superoxide-generating enzyme NADPH oxidase, and invoking modest alterations to antioxidant-response enzymes. The results of this study provide further indirect support for the hypothesis that reduced blood flow to the ONH contributes to axonal injury in glaucoma.

Low glucose dependent decrease of apoptosis and induction of autophagy in breast cancer MCF-7 cells

Cancer cells have developed a number of adaptation mechanisms involving the signal activation of the transduction pathways, which promotes the progression and metastasis. Our results showed that the percentage of apoptotic MCF-7 cells incubated in the low glucose medium for 48 h was lower in comparison to those cultured in the high glucose medium, despite the high expression of the proapoptotic transcription factor-CHOP. Furthermore, the MCF-7 cells incubated in the low glucose medium for 48 h showed a higher expression of NF-κB p100/p52 subunits compared to cells incubated in the high glucose medium. Moreover, our findings demonstrated that the shortage of glucose strongly induces autophagy in MCF-7 cells. The activation of this process is not associated with the changes in the expression of mTOR kinase. We suggest, that the antiapoptotic chaperone ORP150 induction, transcription factor NF-κB2 activation, and increased autophagy constitute mechanisms protecting the MCF-7 cells against apoptosis.

Unfolding the Role of Large Heat Shock Proteins: New Insights and Therapeutic Implications

Heat shock proteins (HSPs) of eukaryotes are evolutionarily conserved molecules present in all the major intracellular organelles. They mainly function as molecular chaperones and participate in maintenance of protein homeostasis in physiological state and under stressful conditions. Despite their relative abundance, the large HSPs, i.e., Hsp110 and glucose-regulated protein 170 (Grp170), have received less attention compared to other conventional HSPs. These proteins are distantly related to the Hsp70 and belong to Hsp70 superfamily. Increased sizes of Hsp110 and Grp170, due to the presence of a loop structure, result in their exceptional capability in binding to polypeptide substrates or non-protein ligands, such as pathogen-associated molecules. These interactions that occur in the extracellular environment during tissue injury or microbial infection may lead to amplification of an immune response engaging both innate and adaptive immune components. Here, we review the current advances in understanding these large HSPs as molecular chaperones in proteostasis control and immune modulation as well as their therapeutic implications in treatment of cancer and neurodegeneration. Given their unique immunoregulatory activities, we also discuss the emerging evidence of their potential involvement in inflammatory and immune-related diseases.

Oxygen regulates molecular mechanisms of cancer progression and metastasis

Oxygen is the basic molecule which supports life and it truly is "god's gift to life." Despite its immense importance, research on "oxygen biology" has never received the light of the day and has been limited to physiological and biochemical studies. It seems that in modern day biology, oxygen research is summarized in one word "hypoxia." Scientists have focused on hypoxia-induced transcriptomics and molecular-cellular alterations exclusively in disease models. Interestingly, the potential of oxygen to control the basic principles of biology like homeostatic maintenance, transcription, replication, and protein folding among many others, at the molecular level, has been completely ignored. Here, we present a perspective on the crucial role played by oxygen in regulation of basic biological phenomena. Our conclusion highlights the importance of establishing novel research areas like oxygen biology, as there is great potential in this field for basic science discoveries and clinical benefits to the society.

Quantitative Proteomics and Lipidomics Analysis of Endoplasmic Reticulum of Macrophage Infected with Mycobacterium tuberculosis

Even though endoplasmic reticulum (ER) stress associated with mycobacterial infection has been well studied, the molecular basis of ER as a crucial organelle to determine the fate of Mtb is yet to be established. Here, we have studied the ability of Mtb to manipulate the ultrastructural architecture of macrophage ER and found that the ER-phenotypes associated with virulent (H37Rv) and avirulent (H37Ra) strains were different: a rough ER (RER) with the former against a smooth ER (SER) with the later. Further, the functional attributes of these changes were probed by MS-based quantitative proteomics (133 ER proteins) and lipidomics (8 phospholipids). Our omics approaches not only revealed the host pathogen cross-talk but also emphasized how precisely Mtb uses proteins and lipids in combination to give rise to characteristic ER-phenotypes. H37Ra-infected macrophages increased the cytosolic Ca²⁺ levels by attenuating the ATP2A2 protein and simultaneous induction of PC/PE expression to facilitate apoptosis. However, H37Rv inhibited apoptosis and further controlled the expression of EST-1 and AMRP proteins to disturb cholesterol homeostasis resulting in sustained infection. This approach offers the potential to decipher the specific roles of ER in understanding the cell biology of mycobacterial infection with special reference to the impact of host response.

The Endoplasmic Reticulum Chaperone GRP170: From Immunobiology to Cancer Therapeutics

Glucose-regulated protein 170 (GRP170) is the largest member of glucose-regulated protein family that resides in the endoplasmic reticulum (ER). As a component of the ER chaperone network, GRP170 assists in protein folding, assembly, and transportation of secretory or transmembrane proteins. The well documented cytoprotective activity of intracellular GRP170 due to its intrinsic chaperoning property has been shown to provide a survival benefit in cancer cells during tumor progression or metastasis. Accumulating evidence shows that extracellular GRP170 displays a superior capacity in delivering tumor antigens to specialized antigen-presenting cells for cross-presentation, resulting in generation of an anti-tumor immune response dependent on cytotoxic CD8⁺ T cells. This unique feature of GRP170 provides a molecular basis for using GRP170 as an immunostimulatory adjuvant to develop a recombinant vaccine for therapeutic immunization against cancers. This review summarizes the latest findings in understanding the biological effects of GRP170 on cell functions and tumor progression. The immunomodulating activities of GRP170 during interactions with the innate and adaptive arms of the immune system as well as its therapeutic applications in cancer immunotherapy will be discussed.

Deletion of Atf6α impairs astroglial activation and enhances neuronal death following brain ischemia in mice

To dissect the role of endoplasmic reticulum (ER) stress and unfolded protein response in brain ischemia, we investigated the relevance of activating transcription factor 6α (ATF6α), a master transcriptional factor in the unfolded protein response, after permanent middle cerebral artery occlusion (MCAO) in mice. Enhanced expression of glucose-regulated protein78, a downstream molecular chaperone of ATF6α, was observed in both neurons and glia in the peri-infarct region of wild-type mice after MCAO. Analysis using wild-type and Atf6α(-/-) mice revealed a larger infarct volume and increased cell death in the peri-ischemic region of Atf6α(-/-) mice 5 days after MCAO. These phenotypes in Atf6α(-/-) mice were associated with reduced levels of astroglial activation/glial scar formation, and a spread of tissue damage into the non-infarct area. Further analysis in mice and cultured astrocytes revealed that signal transducer and activator of transcription 3 (STAT3)-glial fibrillary acidic protein signaling were diminished in Atf6α(-/-) astrocytes. A chemical chaperone, 4-phenylbutyrate, restored STAT3-glial fibrillary acidic protein signaling, while ER stressors, such as tunicamycin and thapsigargin, almost completely abolished signaling in cultured astrocytes. Furthermore, ER stress-induced deactivation of STAT3 was mediated, at least in part, by the ER stress-responsive tyrosine phosphatase, TC-PTP/PTPN2. These results suggest that ER stress plays critical roles in determining the level of astroglial activation and neuronal survival after brain ischemia.

Roles of 17β-hydroxysteroid dehydrogenase type 10 in neurodegenerative disorders

17β-Hydroxysteroid dehydrogenase type 10 (17β-HSD10) is encoded by the HSD17B10 gene mapping at Xp11.2. This homotetrameric mitochondrial multifunctional enzyme catalyzes the oxidation of neuroactive steroids and the degradation of isoleucine. This enzyme is capable of binding to other peptides, such as estrogen receptor α, amyloid-β, and tRNA methyltransferase 10C. Missense mutations of the HSD17B10 gene result in 17β-HSD10 deficiency, an infantile neurodegeneration characterized by progressive psychomotor regression and alteration of mitochondria morphology. 17β-HSD10 exhibits only a negligible alcohol dehydrogenase activity, and is not localized in the endoplasmic reticulum or plasma membrane. Its alternate name - Aβ binding alcohol dehydrogenase (ABAD) - is a misnomer predicated on the mistaken belief that this enzyme is an alcohol dehydrogenase. Misconceptions about the localization and function of 17β-HSD10 abound. 17β-HSD10's proven location and function must be accurately identified to properly assess this enzyme's important role in brain metabolism, especially the metabolism of allopregnanolone. The brains of individuals with Alzheimer's disease (AD) and of animals in an AD mouse model exhibit abnormally elevated levels of 17β-HSD10. Abnormal expression, as well as mutations of the HSD17B10 gene leads to impairment of the structure, function, and dynamics of mitochondria. This may underlie the pathogenesis of the synaptic and neuronal deficiency exhibited in 17β-HSD10 related diseases, including 17β-HSD10 deficiency and AD. Restoration of steroid homeostasis could be achieved by the supplementation of neuroactive steroids with a proper dosing and treatment regimen or by the adjustment of 17β-HSD10 activity to protect neurons. The discovery of this enzyme's true function has opened a new therapeutic avenue for treating AD.

Proteome analysis reveals roles of L-DOPA in response to oxidative stress in neurons

Background

Parkinson’s disease (PD) is the second most common neurodegenerative movement disorder, caused by preferential dopaminergic neuronal cell death in the substantia nigra, a process also influenced by oxidative stress. L-3,4-dihydroxyphenylalanine (L-DOPA) represents the main treatment route for motor symptoms associated with PD however, its exact mode of action remains unclear. A spectrum of conflicting data suggests that L-DOPA may damage dopaminergic neurons due to oxidative stress whilst other data suggest that L-DOPA itself may induce low levels of oxidative stress, which in turn stimulates endogenous antioxidant mechanisms and neuroprotection.

Results

In this study we performed a two-dimensional gel electrophoresis (2DE)-based proteomic study to gain further insight into the mechanism by which L-DOPA can influence the toxic effects of H₂O₂ in neuronal cells. We observed that oxidative stress affects metabolic pathways as well as cytoskeletal integrity and that neuronal cells respond to oxidative conditions by enhancing numerous survival pathways. Our study underlines the complex nature of L-DOPA in PD and sheds light on the interplay between oxidative stress and L-DOPA.

Conclusions

Oxidative stress changes neuronal metabolic routes and affects cytoskeletal integrity. Further, L-DOPA appears to reverse some H₂O₂-mediated effects evident at both the proteome and cellular level.

Modulation of Kaposi's sarcoma-associated herpesvirus interleukin-6 function by hypoxia-upregulated protein 1

Kaposi's sarcoma-associated herpesvirus (KSHV, also called human herpesvirus 8) is linked to the development of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). KSHV expresses several proteins that modulate host cell signaling pathways. One of these proteins is viral interleukin-6 (vIL-6), which is a homolog of human IL-6 (hIL-6). vIL-6 is able to prevent apoptosis and promote proinflammatory signaling, angiogenesis, and cell proliferation. Although it can be secreted, vIL-6 is mainly an intracellular protein that is retained in the endoplasmic reticulum (ER). We performed affinity purification and mass spectrometry to identify novel vIL-6 binding partners and found that a cellular ER chaperone, hypoxia-upregulated protein 1 (HYOU1), interacts with vIL-6. Immunohistochemical staining reveals that both PEL and KS tumor tissues express significant amounts of HYOU1. We also show that HYOU1 increases endogenous vIL-6 protein levels and that HYOU1 facilitates vIL-6-induced JAK/STAT signaling, migration, and survival in endothelial cells. Furthermore, our data suggest that HYOU1 also modulates vIL-6's ability to induce CCL2, a chemokine involved in cell migration. Finally, we investigated the impact of HYOU1 on cellular hIL-6 signaling. Collectively, our data indicate that HYOU1 is important for vIL-6 function and may play a role in the pathogenesis of KSHV-associated cancers.

IMPORTANCE

KSHV vIL-6 is detectable in all KSHV-associated malignancies and promotes tumorigenesis and inflammation. We identified a cellular protein, called hypoxia-upregulated protein 1 (HYOU1), that interacts with KSHV vIL-6 and is present in KSHV-infected tumors. Our data suggest that HYOU1 facilitates the vIL-6-induced signaling, migration, and survival of endothelial cells.

Deletion of N-myc downstream-regulated gene 2 attenuates reactive astrogliosis and inflammatory response in a mouse model of cortical stab injury

N-myc downstream-regulated gene 2 (Ndrg2) is a differentiation- and stress-associated molecule predominantly expressed in astrocytes in the CNS. In this study, we examined the expression and the role of Ndrg2 after cortical stab injury. We observed that Ndrg2 expression was elevated in astrocytes surrounding the wounded area as early as day 1 after injury in wild-type mice. Deletion of Ndrg2 resulted in lower induction of reactive astroglial and microglial markers in the injured cortex. Histological analysis showed reduced levels of hypertrophic changes in astrocytes, accumulation of microglia, and neuronal death in Ndrg2(-/-) mice after injury. Furthermore, activation of the IL-6/signal transducer and activator of transcription 3 (STAT3) pathway, including the expression of IL-6 family cytokines and phosphorylation of STAT3, was markedly reduced in Ndrg2(-/-) mice after injury. In a culture system, both of Il6 and Gfap were up-regulated in wild-type astrocytes treated with forskolin. Deletion of Ndrg2 attenuated induction of these genes, but did not alter proliferation or migration of astrocytes. Adenovirus-mediated reexpression of Ndrg2 rescued the reduction of IL-6 expression after forskolin stimulation. These findings suggest that Ndrg2 plays a key role in reactive astrogliosis after cortical stab injury through a mechanism involving the positive regulation of IL-6/STAT3 signaling.

Genetic, transcriptomic, and epigenetic studies of HIV-associated neurocognitive disorder

The Human Genome Project, coupled with rapidly evolving high-throughput technologies, has opened the possibility of identifying heretofore unknown biological processes underlying human disease. Because of the opaque nature of HIV-associated neurocognitive disorder (HAND) neuropathogenesis, the utility of such methods has gained notice among NeuroAIDS researchers. Furthermore, the merging of genetics with other research areas has also allowed for application of relatively nascent fields, such as neuroimaging genomics, and pharmacogenetics, to the context of HAND. In this review, we detail the development of genetic, transcriptomic, and epigenetic studies of HAND, beginning with early candidate gene association studies and culminating in current "omics" approaches that incorporate methods from systems biology to interpret data from multiple levels of biological functioning. Challenges with this line of investigation are discussed, including the difficulty of defining a valid phenotype for HAND. We propose that leveraging known associations between biology and pathology across multiple levels will lead to a more reliable and valid phenotype. We also discuss the difficulties of interpreting the massive and multitiered mountains of data produced by current high-throughput omics assays and explore the utility of systems biology approaches in this regard.

Glucose-regulated proteins in cancer: molecular mechanisms and therapeutic potential

The glucose-regulated proteins (GRPs) are stress-inducible chaperones that mostly reside in the endoplasmic reticulum or the mitochondria. Recent advances show that the GRPs have functions that are distinct from those of the related heat shock proteins, and they can be actively translocated to other cellular locations and assume novel functions that control signalling, proliferation, invasion, apoptosis, inflammation and immunity. Mouse models further identified their specific roles in development, tumorigenesis, metastasis and angiogenesis. This Review describes their discovery and regulation, as well as their biological functions in cancer. Promising agents that use or target the GRPs are being developed, and their efficacy as anticancer therapeutics is also discussed.

Transcriptome analysis of HIV-infected peripheral blood monocytes: gene transcripts and networks associated with neurocognitive functioning

Immunologic dysfunction, mediated via monocyte activity, has been implicated in the development of HIV-associated neurocognitive disorder (HAND). We hypothesized that transcriptome changes in peripheral blood monocytes relate to neurocognitive functioning in HIV+ individuals, and that such alterations could be useful as biomarkers of worsening HAND.

METHODS

mRNA was isolated from the monocytes of 86 HIV+ adults and analyzed with the Illumina HT-12 v4 Expression BeadChip. Neurocognitive functioning, HAND diagnosis, and other clinical and virologic variables were determined. Data were analyzed using standard expression analysis and weighted gene co-expression network analysis (WGCNA).

RESULTS

Neurocognitive functioning was correlated with multiple gene transcripts in the standard expression analysis. WGCNA identified two nominally significant co-expression modules associated with neurocognitive functioning, which were enriched with genes involved in mitotic processes and translational elongation.

CONCLUSIONS

Multiple modified gene transcripts involved in inflammation, cytoprotection, and neurodegeneration were correlated with neurocognitive functioning. The associations were not strong enough to justify their use as biomarkers of HAND; however, the associations of two co-expression modules with neurocognitive functioning warrant further exploration.

High molecular weight stress proteins: Identification, cloning and utilisation in cancer immunotherapy

Although the large stress/heat shock proteins (HSPs), i.e. Hsp110 and Grp170, were identified over 30 years ago, these abundant and highly conserved molecules have received much less attention compared to other conventional HSPs. Large stress proteins act as molecular chaperones with exceptional protein-holding capability and prevent the aggregation of proteins induced by thermal stress. The chaperoning properties of Hsp110 and Grp170 are integral to the ability of these molecules to modulate immune functions and are essential for developing large chaperone complex vaccines for cancer immunotherapy. The potent anti-tumour activity of the Hsp110/Grp170-tumour protein antigen complexes demonstrated in preclinical studies has led to a phase I clinical trial through the National Cancer Institute's rapid access to intervention development (RAID) programme that is presently underway. Here we review aspects of the structure and function of these large stress proteins, their roles as molecular chaperones in the biology of cell stress, and prospects for their use in immune regulation and cancer immunotherapy. Lastly, we will discuss the recently revealed immunosuppressive activity of scavenger receptor A that binds to Hsp110 and Grp170, as well as the feasibility of targeting this receptor to promote T-cell activation and anti-tumour immunity induced by large HSP vaccines and other immunotherapies.

Age-associated differences in gene expression in response to delayed anesthetic preconditioning

Evidence suggests that the protective benefits of anesthetic preconditioning (APC) are significantly attenuated in the aged myocardium. In this study, we investigated the effect of aging on gene expression in delayed APC. Hearts from Fischer 344 rats, age 4 or 24 months, were divided into five groups: control; ischemia/reperfusion (I/R); and delayed APC at 6, 12, and 24 h. Whole-genome array was studied using Affymetrix Rat Genome 230 2.0 array. Data were analyzed for significant ≥2.0-fold changes in gene expression. Microarray results were confirmed by quantitative real-time reverse transcription-polymerase chain reaction. Of the 28,000 genes represented on the Affymetrix Rat Genome 230 2.0 Microarray chip, 24 transcripts in 6 h APC, 28 in 12 h APC, and 28 in 24 h APC group displayed significant up-regulation in mRNA levels, and 70 transcripts in 6 h APC, 101 in 12 h APC, and 82 in 24 h APC displayed significant down-regulation in young rat hearts. These altered genes fall into functional categories of cell defense/death, cell structure, gene expression/protein synthesis, inflammatory response/growth/remodeling, and signaling/communication. Although alterations for some genes were in common, the numbers of changed genes in old rats were markedly and consistently lower than the young rats. Twenty-four hour delayed APC also significantly reduced infarct size and improved myocardial left ventricular function in young hearts, effects that were not observed in old rat hearts. We concluded that delayed APC profoundly and differentially affected gene expression profiles of the cardiomyocyte in an age-associated pattern. The impaired genomic response to delayed APC could underlie the loss of the protective benefits of preconditioning in aged hearts.

Retinal proteome analysis in a mouse model of oxygen-induced retinopathy

To identify proteins that are involved in the molecular mechanisms of oxygen-induced retinopathy (OIR), a well-established model of blinding ischemic retinopathy, we quantitatively analyzed the retinal proteome in a mouse model of OIR. OIR was induced by exposing C57BL/6 mice on postnatal day 7 (P7) to 75% hyperoxia for 5 days, followed by 5 days in room air. Retinas from mice on P12 and P17, the hyperoxic and hypoxic phases, respectively, and control groups were examined using isobaric tags for relative and absolute quantitation (iTRAQ) and nano-LC-ESI-MS/MS. In total, 1422 retinal proteins were identified: 699 from the iTRAQ experiment and 1074 by nano-LC-ESI-MS/MS. Compared with control retinas in the iTRAQ study, OIR retinas upregulated and downregulated 21 and 17 proteins, respectively, in P17 retinas and 25 and 14 proteins, respectively, in P12 retinas. Of the differentially expressed proteins, the retinal expression of crystallin proteins, Müller cell-associated proteins, neurodegeneration-associated proteins, and angiogenesis-associated proteins, such as 150-kDa oxygen-regulated protein (ORP150), were analyzed. ORP150 colocalized to the neovascular tufts, and knockdown of ORP150 by siRNA decreased the levels of secreted VEGF in cultured retinal pigment epithelial cells. Moreover, intravitreal administration of siRNA targeting ORP150 significantly reduced the retinal neovascularization in OIR. In conclusion, our proteomic discovery method, coupled with targeted approaches, revealed many proteins that were differentially regulated in the mouse model of OIR. These proteins, including ORP150, are potential novel therapeutic targets for the treatment of proliferative ischemic retinopathy.

Expression of 150-kDa oxygen-regulated protein (ORP150) stimulates bleomycin-induced pulmonary fibrosis and dysfunction in mice

Idiopathic pulmonary fibrosis (IPF) involves pulmonary injury associated with inflammatory responses, fibrosis and dysfunction. Myofibroblasts and transforming growth factor (TGF)-β1 play major roles in the pathogenesis of this disease. Endoplasmic reticulum (ER) stress response is induced in the lungs of IPF patients. One of ER chaperones, the 150-kDa oxygen-regulated protein (ORP150), is essential for the maintenance of cellular viability under stress conditions. In this study, we used heterozygous ORP150-deficient mice (ORP150(+/-) mice) to examine the role of ORP150 in bleomycin-induced pulmonary fibrosis. Treatment of mice with bleomycin induced the expression of ORP150 in the lung. Bleomycin-induced inflammatory responses were slightly exacerbated in ORP150(+/-) mice compared to wild-type mice. On the other hand, bleomycin-induced pulmonary fibrosis, alteration of lung mechanics and respiratory dysfunction was clearly ameliorated in the ORP150(+/-) mice. Bleomycin-induced increases in pulmonary levels of both active TGF-β1 and myofibroblasts were suppressed in ORP150(+/-) mice. These results suggest that although ORP150 is protective against bleomycin-induced lung injury, this protein could stimulate bleomycin-induced pulmonary fibrosis by increasing pulmonary levels of TGF-β1 and myofibroblasts.

Early proteome analysis of rat pancreatic acinar AR42J cells treated with taurolithocholic acid 3-sulfate

BACKGROUND

Bile acids are the initiating factors of biliary acute pancreatitis. Bile acids can induce the activation of intracellular zymogen, thus leading injury in pancreatic acinar cells. Pathological zymogen activation in pancreatic acinar cells is a common feature of all types of acute pancreatitis. The proteins expressed in pancreatic acinar cells during the activation of zymogen may determine the severity of acute pancreatitis. The present study aims to determine the differentially expressed proteins in taurolithocholic acid 3-sulfate-stimulated pancreatic acinar cells as an in vitro model for acute pancreatitis.

METHODS

Rat pancreatic acinar AR42J cells were treated with taurolithocholic acid 3-sulfate for 20 min. Laser confocal scanning microscopy and flow cytometry were used to detect activated trypsinogen in pancreatic acinar AR42J cells. After the determination of trypsinogen activation, proteome analysis was performed to identify the proteins differentially expressed in taurolithocholic acid 3-sulfate-treated cells and non-treated cells.

RESULTS

After treatment with taurolithocholic acid 3-sulfate for 20 min, the activation of trypsinogen in AR42J cells was concurrent with changes in the protein expression profile. Thirty-nine differentially expressed proteins were detected; among these, 23 proteins were up-regulated and 16 proteins were down-regulated. KEGG analysis indicated that these proteins are involved in cellular metabolic pathways, cellular defensive mechanisms, intracellular calcium regulation and cytoskeletal changes.

CONCLUSION

The expression of proteins in the pancreatic acinar cell changes at the early stage of biliary acute pancreatitis. These differentially expressed proteins will provide valuable information to understand the pathophysiologic mechanism biliary acute pancreatitis and may be useful for prognostic indices of acute pancreatitis.

Involvement of oxygen-regulated protein 150 in AMP-activated protein kinase-mediated alleviation of lipid-induced endoplasmic reticulum stress

Hepatocytes show endoplasmic reticulum (ER) stress when exposed to lipotoxic stimuli such as hyperlipidemia. Recent work has revealed that AMP- activated protein kinase (AMPK) can mitigate ER stress. In this study we investigated the impact of AMPK on lipid-induced ER stress in hepatocytes and its underlying molecular mechanism. Treatment with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an AMPK agonist, or overexpression of a constitutively active AMPK significantly suppressed lipid-mediated ER stress, leading to marked protection against lipotoxic death. Incubation with AICAR and constitutively active AMPK overexpression induced the expression of an ER-associated chaperone, 150-kDa oxygen-regulated protein (ORP150), at both the mRNA and protein levels in hepatocytes. Forkhead box O1 (FOXO1) was identified as the critical transcription factor regulating ORP150 expression because silencing FOXO1 expression prevented the induction of ORP150 expression by AMPK. In contrast, overexpression of FOXO1-ADA promoted ORP150 expression in hepatocytes. FOXO1 bound directly to the ORP150 promoter, which was enhanced in the presence of AICAR. AMPK acts to activate FOXO1 by increasing its deacetylation and transcriptional activity via silent mating type information regulation 2 homolog 1 (SIRT1). Furthermore, AICAR infusion enhanced ORP150 expression, resulting in the marked amelioration of hepatic ER stress and apoptosis in C57BL/6J mice fed a high fat diet. Our results reveal a novel mechanism by which AMPK regulates ER homeostasis in hepatocytes and suggest that AMPK has a protective role against hypercholesterolemia-related liver damage.

Redox control of endoplasmic reticulum function

The lumen of the endoplasmic reticulum constitutes a separate intracellular compartment with a special proteome and metabolome. The redox conditions of the organelle are also characteristically different from those of the other subcellular compartments. The luminal environment has been considered more oxidizing than the cytosol due to the presence of oxidative protein folding. However, recent observations suggest that redox systems in reduced and oxidized states are present simultaneously. The concerted action of membrane transporters and oxidoreductase enzymes maintains the oxidized state of the thiol-disulfide and the reduced state of the pyridine nucleotide redox systems, which are prerequisites for the normal redox reactions localized in the organelle. The powerful thiol-oxidizing machinery of oxidative protein folding continuously challenges the local antioxidant defense. Alterations of the luminal redox conditions, either in oxidizing or reducing direction, affect protein processing, are sensed by the accumulation of misfolded/unfolded proteins, and may induce endoplasmic reticulum stress and unfolded protein response. The activated signaling pathways attempt to restore the balance between protein loading and processing and induce programmed cell death if these attempts fail. Recent findings strongly support the involvement of redox-based endoplasmic reticulum stress in a plethora of human diseases, either as causative agents or as complications.

Berberine reduces endoplasmic reticulum stress and improves insulin signal transduction in Hep G2 cells

AIM

Endoplasmic reticulum (ER) stress plays an important role in the pathogenesis of insulin resistance and pancreatic beta-cell dysfunction. The aim of this study is to investigate whether the insulin-sensitizing action of berberine is related to reducing ER stress.

METHODS

ER stress in cultured Hep G2 cells was induced with tunicamycin. Cells were pretreated with berberine in combination with or without insulin. The concentration of glucose was measured by glucose oxidase method. The molecular markers of ER stress, including ORP150, PERK, and eIF2 alpha were analyzed by Western blot or real time PCR. The activity of JNK was also evaluated. Moreover, the insulin signaling proteins such as IRS-1 and AKT were determined by Western blot.

RESULTS

The production of glucose stimulated with insulin was reduced. The expressions of ORP150 was decreased both in gene and protein levels when cells were pretreated with berberine, while the activation of JNK was blocked. The levels of phosphorylation both on PERK and eIF2 alpha were inhibited in cells pretreated with berberine. The level of IRS-1 ser(307) phosphorylation was decreased, whereas IRS-1 tyr phosphorylation was increased notablely. AKT ser(473) phosphorylation was also enhanced significantly in the presence of berberine.

CONCLUSION

The antidiabetic effect of berberine in Hep G2 cells maybe related to attenuation of ER stress and improvement of insulin signal transduction.

Interactions between Kar2p and its nucleotide exchange factors Sil1p and Lhs1p are mechanistically distinct

Kar2p, an essential Hsp70 chaperone in the endoplasmic reticulum of Saccharomyces cerevisiae, facilitates the transport and folding of nascent polypeptides within the endoplasmic reticulum lumen. The chaperone activity of Kar2p is regulated by its intrinsic ATPase activity that can be stimulated by two different nucleotide exchange factors, namely Sil1p and Lhs1p. Here, we demonstrate that the binding requirements for Lhs1p are complex, requiring both the nucleotide binding domain plus the linker domain of Kar2p. In contrast, the IIB domain of Kar2p is sufficient for binding of Sil1p, and point mutations within IIB specifically blocked Sil1p-dependent activation while remaining competent for activation by Lhs1p. Taken together, these results demonstrate that the interactions between Kar2p and its two nucleotide exchange factors can be functionally resolved and are thus mechanistically distinct.

Study of narrow band millimeter-wave potential interactions with endoplasmic reticulum stress sensor genes

The main purpose of this article is to study potential biological effects of low-power millimeter waves (MMWs) on endoplasmic reticulum (ER), an organelle sensitive to a wide variety of environmental insults and involved in a number of pathologies. We considered exposure frequencies around 60 GHz in the context of their near-future applications in wireless communication systems. Radiations within this frequency range are strongly absorbed by oxygen molecules, and biological species have never been exposed to such radiations in natural environmental conditions. A set of five discrete frequencies has been selected; three of them coincide with oxygen spectral lines (59.16, 60.43, and 61.15 GHz) and two frequencies correspond to the spectral line overlap regions (59.87 and 60.83 GHz). Moreover, we used a microwave spectroscopy approach to select eight frequencies corresponding to the spectral lines of various molecular groups within 59-61 GHz frequency range. The human glial cell line, U-251 MG, was exposed or sham-exposed for 24 h with a peak incident power density of 0.14 mW/cm(2). The average specific absorption rate (SAR) within the cell monolayer ranges from 2.64 +/- 0.08 to 3.3 +/- 0.1 W/kg depending on the location of the exposed well. We analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR) the level of expression of two endogenous ER-stress biomarkers, namely, the chaperones BiP/GRP78 and ORP150/GRP170. It was found that exposure to low-power MMW does not significantly modify the mRNA levels of these stress-sensitive genes suggesting that ER homeostasis is not altered by low-power MMW at the considered frequencies.

Alteration of the unfolded protein response modifies neurodegeneration in a mouse model of Marinesco-Sjögren syndrome

Endoplasmic reticulum (ER) stress has been linked to the onset and progression of many diseases. SIL1 is an adenine nucleotide exchange factor of the essential ER lumen chaperone HSPA5/BiP that senses ER stress and is involved in protein folding. Mutations in the Sil1 gene have been associated with Marinesco-Sjögren syndrome, hallmarks of which include ataxia and cerebellar atrophy. We have previously shown that loss of SIL1 function in mouse results in ER stress, ubiquitylated protein inclusions, and degeneration of specific Purkinje cells in the cerebellum. Here, we report that overexpression of HYOU1/ORP150, an exchange factor that works in parallel to SIL1, prevents ER stress and rescues neurodegeneration in Sil1(-/-) mice, whereas decreasing expression of HYOU1 exacerbates these phenotypes. In addition, loss of DNAJC3/p58(IPK), a co-chaperone that promotes ATP hydrolysis by BiP, ameliorates ER stress and neurodegeneration in Sil1(-/-) mice. These findings suggest that alterations in the nucleotide exchange cycle of BiP cause ER stress and neurodegeneration in Sil1-deficient mice. Our results present the first evidence of important genetic modifiers of Marinesco-Sjögren syndrome, and provide additional pathways for therapeutic intervention for this, and other ER stress-induced, diseases.

Current insights on the biology and clinical aspects of VEGF regulation

Vascular endothelial growth factor (VEGF) is a key molecule that orchestrates the formation and function of vascular networks. Impaired regulation of angiogenesis is implicated in a number of pathologic states. For instance, neoplasias exhibit uncontrolled angiogenesis, whereas ischemia and states of vascular insufficiency involve reduced VEGF activity. As the role of VEGF has been elucidated in these disease processes, its therapeutic role has been developed. The Food and Drug Administration has approved several anti-VEGF agents for treating colorectal, lung, and kidney cancer. VEGF-inducing agents have also been used experimentally to induce angiogenesis in patients with critical limb ischemia. As more knowledge is gathered about the biology of VEGF and its receptors, there is greater promise for therapeutic modulation of VEGF expression. The purpose of this review is to describe the various therapeutic and biologic factors that regulate the expression of VEGF.